Bird Guilds Research Articles

Natural grazing by horses and cattle promotes bird diversity in a restored European alluvial grassland.

A challenge in grassland conservation is to maintain both the openness and the heterogeneity of the habitat to support the diversity of their animal communities, including birds-a taxon that is known to be sensitive to disturbance. An increasingly used management tool in European grassland conservation, especially in rewilding projects, is grazing by large herbivores such as horses and cattle. These grazers are believed to create and maintain patchy landscapes that promote diversity and richness of other species, but their influence on birds is often debated by conservationists, who raise concerns about the impact of disturbance by the grazers. Our aim was to examine the relationship between the abundance and species richness of birds across four foraging guilds and the area utilization patterns of Highland cattle and Konik horses in an alluvial grassland in France. We also aimed to examine the influence of land cover and season on the spatial distribution, including abundance and species richness, of different bird guilds present in the grazed area. We used GPS-collars on all grazers and recorded their positions on an hourly basis over a study period of 1.5 years, assessing patterns of area usage. We counted birds weekly along three transects to describe their distribution within the grazed area and carried out land-cover surveys to describe the habitat. To assess how species richness and abundance of birds of different guilds were related to grazer density, season, and habitat characteristics, we used GAMM models in a spatially explicit framework. We also compared bird numbers at our main study site with a nearby non-grazed control area. The number of birds in the grazed area was about twice the number in the non-grazed control area. Within the grazed area, the abundance of open-area foraging birds increased with increasing grazer density. The number of woodland-foraging birds was also positively correlated with grazer density but less so than open-area foraging birds. The number of individuals in the aerial and wetland bird guilds was not correlated with the density of grazers. Most bird species and individuals were observed on open landscapes scattered with woody patches and waterbodies, and on areas with moderate grazer density. Low-intensity grazing represents a potentially important management tool in creating heterogeneity in alluvial grasslands, thereby promoting suitable habitat for a diverse assemblage of bird species.

Habitat use of Amazonian birds varies by age and foraging guild along a disturbance gradient.

Patterns of habitat use directly influence a species' fitness, yet for many species an individual's age can influence patterns of habitat use. However, in tropical rainforests, which host the greatest terrestrial species diversity, little is known about how age classes of different species use different adjacent habitats of varying quality. We use long-term mist net data from the Amazon rainforest to assess patterns of habitat use among adult, adolescent (teenage) and young understory birds in forest fragments, primary and secondary forest at the Biological Dynamics of Forest Fragments Project in Brazil. Insectivore adults were most common in primary forest, adolescents were equally likely in primary and secondary forest, and all ages were the least common in forest fragments. In contrast to insectivores, frugivores and omnivores showed no differences among all three habitat types. Our results illustrate potential ideal despotic distributions among breeding populations of some guilds of understory birds where adult insectivores may competitively exclude adolescent individuals from primary forest. Secondary forest recovery appears to hold promise as a breeding habitat for frugivore and omnivore species but only as a pre-breeding habitat for insectivores, but as the forest ages, the demographic structure of bird populations should match that of primary forest.

Seasonal fluctuations in diversity and foraging guild of water birds at Navkhala Pond near Nagbhid in Maharashtra, India

Seasonal fluctuations in diversity and foraging guild of water birds at Navkhala Pond near Nagbhid in Maharashtra, India

The spatio‐temporal influences of habitat heterogeneity on the community structure of avian feeding guilds in human‐dominated landscapes of the East African miombo woodlands

AbstractHabitat heterogeneity plays a vital ecological role in influencing community ecology dynamics. We evaluated the relationship between habitat heterogeneity and land‐use cover with avian community structure in the human‐dominated landscape of the Katavi‐Rukwa ecosystem in Tanzania. We used the fixed‐radius point count method to record birds in different habitats. We calculated the relative abundances and the Shannon‐Wiener diversity index of bird guilds across habitats as well as the Normalised Difference Vegetation Index (NDVI) and estimated land‐use cover of the study area from Landsat 8 images. We grouped birds into five major guilds: Insectivore, Granivore, Omnivore, Carnivore and Nectarivore. Among the guilds, Insectivores, Omnivores, Nectarivores and Carnivores were positively correlated with an increase in NDVI, while Granivores were negatively correlated with an increase in NDVI. Among the habitats, woodland had high species diversity whereas riverine had low species diversity. Our findings highlight the importance of habitat heterogeneity in biodiversity conservation in human‐dominated landscapes, and we suggest implementing conservation in these landscapes.

Status, Diversity, and Feeding Guilds of Avifauna in the Mining Area

Birds contribute to the ecosystem by delivering a variety of ecological services. Birds help the ecology by performing a number of ecological functions. Specific habitats determine bird distribution and community structure. The variety and feeding guilds of birds in various land covers were studied at PT. Vale Indonesia’s mining concession. We studied birds’ variety, status, and feeding guilds in three distinct land covers using the point count methods: i) primary dryland forest; ii) secondary dryland forest; and iii) shrubs. Data were obtained from January 20th to February 24th, 2020. There were 38 species from 24 families reported. We discovered 11 Sulawesi endemic species, and 1 vulnerable species. Secondary dryland forest species composition was more similar to primary dryland forest than to shrubs. Carnivores, frugivores, granivores, insectivores, nectarivores, and piscivores make up the fowl. The insectivore bird composition was the highest, while the piscivore bird composition was the lowest. The availability of food supplies and vegetation characteristics may be critical to the diversity of birds in any ecosystem. As a result, this study indicates that land-cover alteration and modification may have an impact on bird diversity structure. Maintaining vegetation as a source of food and habitat for birds is crucial for bird conservation.

From small waterbodies to large multi-service providers: Assessing their ecological multifunctionality for terrestrial birds in Mediterranean agroecosystems

Agricultural intensification has caused a rapid loss of singular landscape elements worldwide, such as farmland ponds, hedgerows and field margins, leading to a steep decline in farmland bird populations. Farmland ponds and traditional small waterbodies (SWB) have been recently reported to support species-rich bird communities at landscape scale in several agroecosystems. However, a comprehensive assessment on the potential ecological functions provided by SWB to terrestrial birds has been never conducted. Here, we used data from breeding bird surveys at 39 traditional SWB to highlight the variety and magnitude of ecological functions provided to terrestrial birds. These SWB belonged to three different structural types and were spread along an environmental gradient in Mediterranean agroecosystems from southeastern Spain. We identified up to six cross-system services benefiting different functional guilds of terrestrial birds. Apart from to the well-documented supply of drinking water, traditional SWB delivered other ecologically relevant and commonly overlooked services to terrestrial birds, such as the provision of bathing sites, essential food resources (e.g., emerging insects), nest-building material and suitable adjacent perches for territorial display or thermoregulation. Structural and environmental variables at waterbody scale played an important role as determinants of the recorded ecological functions. Importantly, most of these ecological functions were evenly observed across the three types of traditional SWB, thus supporting the key role of these singular landscape elements for bird conservation regardless their structural attributes. Agri-environment schemes and farmland biodiversity conservation strategies should account for the ecological multifunctionality of traditional SWB by ensuring the protection and nature-friendly management of these valuable habitats, as well as by promoting the diversity of microhabitats at SWB scale.

Colonial waterbirds provide persistent subsidies to swamp forests along an estuarine island food chain.

Birds are excellent vectors of allochthonous matter and energy due to their high mobility, with more intense flow when waterbirds congregate in breeding colonies, feeding in surrounding aquatic and terrestrial areas, and promoting nutritional pulses to nutrient-poor environments. In southern Brazil, a swamp forest on an estuarine island is used by waterbirds for breeding, providing an opportunity to investigate the potential effects of transport of matter between nutrient-rich environments. Soil, plants, invertebrates, and blood from terrestrial birds were collected and stable isotopes compared to similar organisms in a control site without heronries. Values of δ15N and δ13C from waterbirds were higher in the colony in comparison to the control site (spatial effect). The enrichment of 15N and 13C provided during the active colony period persisted after the breeding period, especially for δ15N, which was higher in all compartments (temporal effect). Moreover, the enrichment of 15N occurred along the entire trophic chain (vertical effect) in the colony environment, including different guilds of invertebrates and land birds. The enrichment in 13C seems to lose strength and was mostly explained by factors such as trophic guild rather than site, especially in birds. Bayesian mixture models with terrestrial vs. estuarine endpoints demonstrated that all organisms from both colony and control environments had assimilated estuarine matter. Finally, detritivorous invertebrates showed greater assimilation when compared to other guilds. This study demonstrates that adjacent nutrient-rich environments, such as palustrine forests and estuaries, are nutritionally enriched in several dimensions from nearby autochthonous subsidies that are maintained throughout the year.

Fire responses by bird guilds and species in heathy dry forests in central Victoria, Australia

Predicted increases in fire frequency and extent are being realised across Australia, bringing changes to the fire regime which may influence the availability of essential resources required by birds. However, few studies have examined either the impacts of fire frequency on birds or the impacts from both wildfire and planned burns, combined. Birds were surveyed eight times across 84 sites in heathy dry forests in central Victoria, south-east Australia, from 2012 to 2014. Fire history records were retrieved from the 1970’s onwards, the time from which accurate planned burn records were kept. We developed mixed models to investigate how birds responded to time-since-fire and fire frequency, analysing total bird abundance, ten foraging guilds and 30 individual species. We found distinct responses by all modelled guilds and species to time-since-fire, along with evidence for responses to fire frequency. The greatest shifts in species’ abundances occurred during the first ten years post fire, with bird species commonly present across the stages greater than ten years since fire. For total bird abundance there was no statistically detectible difference between recently burnt forest (0-6 months) and other age classes. However, some guilds showed a significant drop in abundance in newly burnt vegetation (e.g. bark foragers, damp ground insectivores, those that feed on seeds close to the ground, tall shrub foragers). It is with guild and species’ responses that more differences across vegetation age classes became apparent. Significant increases in abundance were apparent in both the regrowth and new growth vegetation age classes, compared with older habitat (e.g. canopy foragers, damp ground insectivores, tall shrub foragers); open ground foragers were especially common in post-fire regrowth but then significantly declined. Other responses were more complex, with species’ preferences reflecting their foraging ecology. Some birds showed preferences across two age classes: sites that were young post-fire regrowth (6 months–2.5 years since fire) along with sites of old habitat (>35 years since fire), (e.g. Crimson Rosella, Scarlet Robin, Sulphur-crested Cockatoo), while some ground-foraging species became scarce in dense new-growth vegetation that appears 2.5–10 years post fire (e.g. Australian Magpie, Laughing Kookaburra and White-winged Chough). Such species may deserve specific management strategies to maintain populations in forests where substantial areas are burnt by wildfire or planned burns, over short periods of time. The model for total bird abundance showed a significant fire frequency response with birds preferring sites twice burnt within 35 years (e.g. bark and canopy-foraging guilds). Four guilds demonstrated a preference for sites frequently burnt, increasing in abundance as number of burns increased (nectarivores, open-ground foragers, seeds in trees foragers, tall shrub foragers). In contrast, two species appeared to prefer sites that had experienced low fire frequencies, a response not common to their guilds. Laughing Kookaburra (carnivore) and White-winged Chough (forages on open ground among trees) generally declined in abundance with increasing fire frequency.

Direct and indirect effects of agricultural land cover on avian biodiversity in eastern Canada

Agriculture is one of the largest threats to global biodiversity. However, most studies have focused only on the direct effects of agriculture on biodiversity, and few have addressed the indirect effects, potentially over or under-estimating the overall impacts of agriculture on biodiversity. The indirect effect is the response not to the agricultural cover types or operations per se, but instead, to the way that agriculture influences the extent and configuration of different types of natural land cover in the landscape. We used structural equation modelling (SEM) to evaluate the direct, indirect, and total effects of agriculture on species richness of three bird guilds: forest birds, shrub-edge birds, and open country birds. We found that forest bird richness was driven by the negative indirect effect of cropland via forest loss. Shrub-edge and open country bird richness increased with the amount of agriculture land covers; however, importantly, we found negative indirect effects of agriculture on both guilds via a reduction in more natural land covers. This latter result highlights how we would have over-estimated the positive effects of agriculture on shrub-edge and open country bird richness had we not measured both direct and indirect effects (i.e., the total effect size is less than the direct effect size). Overall, our results suggest that a bird-friendly agricultural landscape in our region would have forest that is configured to maximize forest edge, and a high proportion of perennial forage within the agricultural portion of the landscape.

Beaver activity and red squirrel presence predict bird assemblages in boreal Canada

AbstractWetlands and predation in boreal ecosystems play essential roles throughout the breeding season for bird assemblages. We found a positive association of beaver activity and a negative influence of American red squirrels (Tamiasciurus hudsonicus) on bird assemblages. We used a multispecies hierarchical model to investigate whether bird communities differ between two major wetland habitats in boreal Canada: beaver ponds and peatland ponds. In addition to including variables such as forest cover and latitude, we adopted a structural equation model approach to estimate the occupancy of American red squirrels and its potential influence on bird communities. Using automated recording stations deployed at 50 ponds, we detected 96 bird species in 2018 and 2019. Bird species were grouped into four taxonomic guilds according to their habitat successional requirements: early successional species, late successional species, generalists, and wetland species. Beaver ponds harbored higher species richness, a pattern driven primarily by early successional species. The occupancy of almost a quarter of the species was lower in the presence of red squirrels. Late successional species responded positively to the cover of forest surrounding the pond. Our results highlight the value of considering acoustic data of red squirrels to quantify habitat quality in boreal forests. We conclude that beaver activity shapes bird assemblages through modification of their habitat, and that some bird guilds are associated negatively with the presence of American red squirrels.

Resurrecting seasonal dynamics in waterbirds after wetland restoration: before-after monitoring highlights the role of a single dominant species.

We compared a set of uni-varied diversity metrics of a guild of water-related birds (hereafter 'waterbirds') before and after a wetland restoration carried out on uncultivated (reclaimed) lands. Over a period of five years, we observed a restart of seasonal waterbirds dynamics after wetland restoration by flooding of abandoned croplands, with a significant increase in all metrics of diversity, more evident in autumn-winter periods. Seasonal thresholds were evident before (2017-2018) and after (2018-2019) the flooding. These dynamics appeared irregular, probably for a different inter-annual suitability of the flooded meadows due to local ecological factors (e.g., change in meteorological regime and in rush-bed vegetation cover). Rarefaction curves, both for richness and diversity, showed how the waterbird community moved towards a greater complexity. Flooded meadow restoration, particularly favoured wintering species in Mediterranean sites, which explained the strong fluctuations in total abundance. At the species level, Northern Lapwing (Vanellus vanellus), absent before restoration, was the most abundant species after flooding, using flooded meadows with its gregarious behaviour. This 'crowding' may be explained also for a lack of similar habitats in the surrounding. Other dominant species (Anas platyrhynchos, Ardea cinerea, Egretta garzetta) showed a significant increase after restoration. Standardized before-after monitoring on medium term time periods seem suitable to evidence inter-annual season dynamics in diversity metrics of waterbird assemblages.

Role of tea plantations in the maintenance of bird diversity in Anji County, China.

Tea plantations support regional sustainable development and have the potential to support more biodiversity than urban open spaces. Numerous studies have shown the value of low-intensity agroecosystems for preserving biodiversity, however tea plantations have received less attention. The relationship between tea plantations and the diversity of macro-organisms, such as birds, is still not fully understood. We investigated the bird diversity and vegetation conditions and calculated landscape metrics in 30 tea plantations in Anji County, Zhejiang Province, China. At these 30 sampling sites, we recorded 262 individuals belonging to 37 species, which were classified into two guilds: nature- and urban-dependent birds. We used cluster analysis to group the sampling sites based on the abundance of the birds. Then we evaluated the effects of associated plant diversity in tea plantations and the surrounding landscape composition on these bird guilds using species association computation and a generalized linear model. The results show that the maintenance of bird diversity by tea plantations benefits both nature- and urban-dependent birds. We found that landscape-scale factors surrounding the tea plantations mainly affected the bird richness due to their habitat selection. Landscape agglomeration and habitat quality were the dominant landscape-scale metrics. Patch-scale factors of tea plantations, especially the vegetation structure, had a strong influence on the abundance of the birds. Nature-dependent birds preferred to occur in tea plantations with perennial herbs, while urban-dependent birds were attracted by the general distributed plants, as annual herbs. Therefore, we concluded that tea plantations play an important role as a transitional zone between natural habitats and urban areas, thus reducing the impact of urbanization and maintaining bird diversity in low-quality habitats.

Assessing the potential disturbance effects on the use of Unmanned Aircraft Systems (UASs) for European vultures research: a review and conservation recommendations

SummaryVultures are among the most threatened bird guilds on the planet and have a unique functional role within ecosystems. They are therefore subject to increasing research interest, calling for standardised study approaches and monitoring methods. The use of Unmanned Aircraft Systems (UASs) is rapidly gaining popularity in ecological research due to technological advances, affordability, and accessibility. This study reviews the existing peer-reviewed publications and grey literature on the responses of European vultures and other comparable species to UASs, and summarises the types of UAS use, their potential disturbance effects on vultures, and the resulting inter- and intra-specific interactions. Our goal was to assess the potential effects of UASs and to provide practical recommendations to optimise their safe use in vulture conservation and research. We acknowledge the potential of UASs to increase research efficiency and reduce research effort, time, and financial cost. Owing to the absence of sufficient data on long-term disturbance effects, we advocate the precautionary principle and offer a set of species-tailored practical recommendations to limit the potential negative effects of UASs and maximise their value in conservation management. We urge that the physiological and long-term impacts on vulture reproduction are considered and call for standardised monitoring protocols and controls on UAS use. Our conclusions and recommendations are particularly aimed at researchers working on vulture conservation and restoration projects worldwide.

Three grassland bird species’ responses to fire and habitat structure in southern Illinois, USA suggest broad benefits of grassland size and plant diversity

Grassland birds are the most rapidly declining bird guild in North America, largely due to extensive habitat loss and fragmentation. Because many grassland bird species have different habitat preferences, managing grasslands to provide habitat for a range of species can be a challenge. We used four years of data from southern Illinois, USA grasslands to estimate the influence of prescribed fire and habitat structure on nest survival, nest density, and abundance of three grassland bird species with different habitat preferences: Dickcissel (<em>Spiza americana</em>), Field Sparrow (<em>Spizella pusilla</em>), and Common Yellowthroat (<em>Geothlypis trichas</em>). We found that Dickcissels exhibited the strongest response to prescribed fire, as nest density and nest survival both increased after previously undisturbed grasslands were burned. Fire may have also benefitted Common Yellowthroats and Field Sparrows by reducing woody cover and increasing bare ground, both of which were characteristics associated with nest survival for these birds. Dickcissel abundance was positively related to plant diversity within a grassland and agriculture in the surrounding landscape (within 400 m of a grassland patch), and negatively related to edge-interior ratio. Field Sparrows demonstrated a positive association with woody cover and proximity to forests. Common Yellowthroats were associated with tall vegetation and agriculture in the surrounding landscape. Both Field Sparrows and Common Yellowthroats associated positively with habitat characteristics that reduced nest survival, suggesting potential adaptive mismatches. Our results suggest that periodic prescribed fire, increased plant diversity, and larger patch size may simultaneously benefit a broad variety of grassland bird species with different habitat preferences.

Bird Community Composition and Functional Guilds Response to Vegetation Structure in Southwest Ethiopia

Shade coffee farms in southwest Ethiopia are known to host high levels of avian biodiversity. However, these farms vary in terms of forest management, which affects their understory, mid-story, crown cover, and canopy closure, and hence their structural complexity. Such differences in vegetation structure can potentially affect the survival of specialist bird species, and shade coffee farms may not equally contribute to avian biodiversity conservation. This study aimed to investigate how avian community composition, richness, and the relative abundance of different bird functional guilds relate to structural differences in vegetation shaped by forest management. Bird guild classification was based on bird species forest dependence, diet type, migration status, nest type, foraging, and nesting strata, and bird communities were surveyed using the Timed Species Counts (TSCs) method. Species turnover in bird communities was evaluated using detrended correspondence analysis and redundancy analysis, whereby multiple regression models were used to examine bird guild responses to vegetation structure. Total bird species richness and relative abundance did not respond to vegetation structure. However, the richness of forest specialists and understory foragers, and the relative abundance of mid-high foragers, all positively related to tree diameter at breast height (DBH) and crown cover, whereas the relative abundance of species with medium levels of forest dependency, mid-high/canopy foragers, and open-nesters were positively related to basal area and canopy cover. This study demonstrates that the relative value of shade coffee farms for avian biodiversity conservation depends on the type of forest management, and that bigger trees with larger crown cover provide a habitat of higher quality to habitat specialist birds.

Avian species richness and abundance show stronger responses to bison grazing intensity than to ecosystem productivity

AbstractTemperate grassland ecosystems are one of the most threatened ecosystems worldwide, and their loss endangers the grassland songbirds that rely upon them. This guild of birds has shown long‐term declines in North America. At the same time, American bison (Bison bison) are becoming more common through reintroductions, and they may make significant modifications to grassland songbird habitat. To support conservation for this guild, we sought to understand the importance of bison grazing and ecosystem productivity to the species richness, occupancy, and abundance of this avian community. We conducted dependent double‐observer bird counts, measured bison grazing intensity with patty counts, and used remote‐sensed normalized difference vegetation index (NDVI) data to measure ecosystem productivity. Our work took place in the National Bison Range near Moiese, Montana and in Yellowstone National Park in Wyoming. We found that species richness was positively correlated with patty counts and had a weak negative correlation with NDVI. Occupancy probability for six of seven grassland songbird species was positively correlated with patty counts, and for six of seven species was negatively correlated with NDVI. Abundance of vesper sparrow (Pooecetes graminueus) and western meadowlark (Sturnella neglecta) were positively correlated with patty counts, although for western meadowlark, this trend became less positive with increasing patty counts. Our work suggests that managers may want to encourage a broad range of bison grazing intensities to ensure that vegetative conditions related to bison grazing are present for all species.

Changes in a Bird Community in an Agricultural Landscape in Northeast Germany between 1999 and 2015

Temporal changes in the bird community of an agricultural landscape in northeast Germany were analysed covering three different analytical foci (landscape-wide, habitat types, sample plots) and two aggregation levels of bird observation data (whole bird community, bird guilds). The analyses are based on a systematic data sampling over two multi-year campaigns (1999–2002; 2013–2015). Our analyses address the question of how changes in the occurrences of agricultural birds (numbers of species and of individuals) at local spots manifest themselves in the landscape as a whole. By summarizing all findings concerning single variables (number of species, observation frequencies, abundances, different habitat types, bird guilds), a dramatic, systematic decline of the bird community at sample plots was discovered between the campaigns, which is not yet recognisable across the whole landscape in terms of species richness. Furthermore, we found that landscape-wide, the birds’ use of habitat changed; the variability between single sample plots increased strongly and most species occurred at fewer sample plots over the whole landscape. Obviously, sample plots with high bird occurrences are becoming more relevant for maintaining bird communities over the whole landscape. Bird community composition changed significantly within the observation period.

Diversity and Feeding Guild of Birds Along Gradient of Revegetated Area in Karst Ecosystem: a Case Study from Rembang, Central Java

In the mining industry, provision of new habitat through land rehabilitation and affforestation is an important step to anticipate the loss of biodiversity, including bird communities. The positive impacts of land rehabilitation and affforestation thus can be identified from results of periodic monitoring. The turnover of bird communities associated with afforestation is related to changes in structural habitat features that provide food and shelter. In this study, we have monitored bird community assemblages and feeding guild structure in revegetated area of karst in Rembang, Central Java. Three locations (EDP, GBC and GBL) were selected and characterized by different land use, vegetational age and floral composition. Surveys were conducted using point count method in early April for three consecutive years (2020-2022). In total, we have identified 32 bird species from 29 genera, 22 families and 9 orders. Most of birds observed considered as generalist, cosmopolitan and well-adapted to various habitat. Total species richness (19.33±3.22 to 20.67±4.12) and value of diversity index (H’ = 2.41±0.14 to 2.56±0.29) were only slightly differed among locations. Species richness and total abundance in each sites tend to increase along periods of observation, suggesting that bird community change in response to further structural habitat changes that occur as vegetations age. Furthermore, higher abundance occurred in larger area or in sites with more native plant species. The feeding guild costisting 7 groups and dominated by insectivore, both based on number of species (46.88%) and individuals (49.07%). Results of the study are expected to help identify more appropriate management of conservation and habitat restoration in the area.

Combining the preferences of residents for neighborhood green spaces and conservation of avian diversity: Case study from Beijing

Cities in China support higher human population densities compared to those in western countries; consequently, the high pressure placed on cultural ecosystem services (CES) provision of residential green spaces might hinder overall human wellbeing and the maintenance of avian diversity. Thus, this study aimed to identify how to meet the main preferences of citizens for residential green spaces while simultaneously enhancing bird diversity in city neighborhoods, generating a win-win scenario for human needs and biodiversity. This study was implemented using 568 questionnaires for residents and GLMM for bird-environment statistical analyses. Residents in Beijing preferred higher levels of bird species richness than individual abundance in neighborhoods. Residential green space appeared to serve as the movement corridor for some rare species, indicating the importance of promoting the presence of migrant bird guilds, which is currently incidental. The cultivation of fruit-bearing shrubby plants was supported by most city residents, and would also promote the presence of migratory birds in green spaces. In contrast, while increasing the width of residential green spaces would benefit migratory birds, it had less public support. This multi-disciplinary study clearly demonstrated that both the quality of life of humans in cities and biodiversity conservation could be efficiently incorporated in green space plans, even under highly urbanized circumstances.

The abundance of four bird guilds and their use of plants in a Mexican dry forest-oak woodland gradient in two contrasting seasons

Abundancia de cuatro gremios alimentarios de aves y su uso de plantas en un gradiente ambiental (bosque seco – bosque de encino) mexicano en dos temporadas contrastantesSe hizo una comparación entre la abundancia de cuatro gremios de aves, su preferencia por buscar alimento en distintas plantas y el suministro de alimento proporcionado por éstas. El estudio se llevó a cabo en un gradiente de vegetación que abarca selva baja y bosque de encino en dos estaciones contrastantes -la época seca y la época húmeda- y en dos años consecutivos. Las aves fueron agrupadas, atendiendo a las maniobras de forrajeo y a las plantas preferidas, como: colibríes, papamoscas de follaje, pizcadores de selva y pizcadores de bosque. Para identificar a estos gremios se emplearon clasificaciones y para identificar las variables que pudieran caracterizar a cada uno de éstos, se utilizó un análisis de correspondencia sin tendencia. Se realizaron censos en 67 parcelas de diámetro fijo. En cada parcela se estimó la cobertura de las plantas y se emplearon correlaciones simples para determinar cuales plantas estaban asociadas con las densidades de cada gremio de aves en las distintas estaciones de los dos años. Las preferencias de búsqueda se estimaron por medio de pruebas de bondad de ajuste. La mayoría de las plantas que estuvieron significativamente correlacionadas con los gremios no fueron las preferidas para buscar alimento, salvo en el caso de los colibríes; éstos estuvieron significativamente correlacionadas con Ipomoea wolcottiana, un árbol con flores muy visitado por estas aves. En el otoño, que es la época húmeda, ni los pizcadores de follaje ni los papamoscas (fundamentalmente insectívoros en esta estación) utilizaron las plantas con mayores densidades de artrópodos. Esto podría deberse a que las densidades totales de artrópodos no necesariamente reflejan las presas más utilizadas. Además, las aves podrían tener una preferencia por aquellas plantas con alimento fácilmente accesible y no necesariamente por aquellas con mayor cantidad de alimento. El que las plantas con mayores coeficientes de correlación en los dos años hayan sido similares en las dos estaciones (independientemente del alimento que proporcionan) también sugiere que éstas representan más a los hábitats preferidos que al alimento disponible. En la época seca sólo en el primer año las densidades de los colibríes estuvieron asociadas con las plantas más utilizadas. Los resultados coinciden con otros estudios realizados en selvas bajas, en donde las plantas preferidas están sólo parcialmente correlacionadas con la distribución de las aves.